Lubricating composition



United States Patent 3,130,831 LUBRHQATING COMPOSITIQN Max J. Wisotsky,University Park, Pan, and Norman R. Gdell, Wappingers Falls, N.Y.,assignors to Texaco lino, New York, N.Y., a corporation of Delaware NoDrawing. Filed Nov. 9, 1962, Ser. No. 236,700 11 Claims. ('Cl. 25242.7)

This invention relates to a lubricating grease composition and to anovel class of thickening agents therefor. More particularly, thepresent invention relates to a lubricating grease composition thickenedwith a particular class of metal chelates of substitutedZ-hydroxyazobenzenes.

Wehave found that certain copper and nickel chelates of haloormethoxy-substituted 3'-halo-2-hydroxyazobenzenes form stable greasecompositions having excellent lubricating properties in synthetic baseoils, such as silicone polymer oils and diester oils.

The copper and nickel chelates of the haloor methoxysubstituted3-halo-2-hydroxyazobenzenes which are employed as grease thickeningagents of the present invention are represented by the general formula:

wherein A is a member selected from the group consisting of methoxy andhalogen, preferably chlorine, and B is a halogen, preferably a chlorine,and wherein M is a member selected from the group consisting of copperand nickel and wherein when M is nickel, A is a halogen, preferablychlorine.

Particularly suitable azobenzene compounds to prepare the copper ornickel chelate thickening agents include5,3'-dichloro-2-hydroxyazobenzene and methoxy- 3' chloro 2hydroxyazobenzene. The particular metal chelating azo compounds employedin the lubricating greases of the present invention as the thickeningagents include the copper and nickel chelates of 5,3'-dichloro-2-hydroxyazobenzene and the copper chelate of 5 -methoxy- 3 chloro 2hydroxyazobenzene. It is indeed surprising that these particularchelates are effective thick: ening agents in lubricating greases whenother chelate compounds, such as the copper or nickel chelate of 5,4dichloro-Z-hydroxyazobenzene, the nickel chelate of 5-methoxy-3'-chloro-2-hydroxyazobenzene and the nickel base oils, such asa silicone polymer base oil or in a diester base oil.

The grease compositions of the present invention comprise a syntheticbase oil having a viscosity in the lubrieating oil viscosity range,containing a copper or nickel chelate of5,3'-dichloro-2-hydroxyazobenzene or the copper chelate of5-methoXy-3-chloro-2hydroxyazobenzene, in an amount sufiicient tothicken said base oil to a grease consistency. In general, thecomposition contains from about to percent of base oil and from 15 to 45percent of the metal chelate, based on the weight of the composition.The grease compositions of the invention usually also contain from 0.5to about 5% by weight of a corrosion inhibitor and in addition, may

contain from about 0.5 to 5% by weight of an amine oxidation inhibitor.

As is understood in the grease art, the grease compositions mayadditionally contain minor amounts of conventional lubricity agents,coloring materials, extreme pressure agents and the like, includingcombinations of these materials.

A preferred lubricating grease composition comprises from about 59 to69% by Weight of a synthetic silicone polymer oil having a viscosity inthe lubricating oil viscosity range, from 30 to 40% by weight of copperor nickel chelate of 5,3'-dichloro-Z-hydroxyazobenzene, 0.5% ofdiphenyl-para-diphenylenediamine as an oxidation inhibitor, and 0.5%N-cocoylsarcosine as a corrosion inhibitor where cocoyl denotes the acylcomponent derived from coconut oil acids.

Satisfactory arylamine oxidation inhibitors include diphenylamine,phenyl-alpha-naphthylamine, para-phenylenediamine, andN,N'-diphenyl-para-phenylenediamine.

Satisfactory corrosion inhibitors include lead naphthenate and thesarcosines including the N-acylsarcosines containing from 8 to about 20carbon atoms in the acyl group such as N-cocoylsarcosine,N-laurylsarcosine and N-stearylsarcosine.

The synthetic base oil may be a silicone polymer base fluid or analiphatic diester fluid.

The silicone polymer base fluids used to form the greases of the presentinvention are compounds having the general formula:

wherein R, R R R R and R are methyl, phenyl, or chlorinated phenylgroups, preferably at least about 35% thereof being methyl groups andwith sufficient chlorinated phenyl groups to give a chlorine content ofat least about 3% by weight to the polymer, and wherein n is an integerof sufficient size to give a polymer having a viscosity in thelubricating oil viscosity range. The preferred silicone oils are thosehaving a viscosity of from about to 600 seconds Saybolt Universal at 100F. and contain about 4 to 12 percent by weight of chlorine.Aparticularly suitable silicone polymer material is the commercialproduct sold under the trade name Versilube F-SO, having an averagemolecular weight of about 3,233, a viscosity of about 189 to 280 secondsSaybolt Universal at 100 F, and containing about 33.6% silicone and7.18% of chlorine by weight. Another suitable silicone polymer basefluid, sold under the trade name Dow F-60, also can be used in thegrease compositions of the invention.

The methylchlorophenylsilicone polymer oil can be employed as the soleoil component, or it may be employed in admixture with minor amounts ofother oils, particularly other synthetic oils, such as, polyethers,polyglycols, diesters, polyesters, or mixtures of such oils.

The aliphatic ester type base fluids for use in the grease compositionsinclude the diesters of primary alcohols and aliphatic dicarboxylicacids. The dicarboxylic acid component usually contains from 6 to 12carbon atoms, but glutaric and succinic acids are also included. Fromthe standpoint of cost and availability, the preferred acids are adipic,sebacic, and az elaic. The primary aliphatic alcohol used to form thediester base fluid usually contains at least 4 carbon atoms and maycontain 30 or more carbon atoms. C to C alcohols are most commonly used.Specific examples of the dialkyl esters of aliphatic dicarboxylic acidswhich are the preferred base fluid bases for use in the greasecomposition of the invention are as follows: dibutyl azelate,di-Z-ethylhexyl azelate, didodecyl azelate, ditridecyl azelate, dihexyl.

sebacate, di-2'ethylhexyl sebacate, dihexadecyl sebacate,di-Z-ethylhexyl adipate, and diisooctyl adipate. A particularlypreferred aliphatic diester base fluid oil is ditridecyl sebacate.

The aliphatic diester base oil can be employed as the sole oil componentin the grease compositions of this invention, or the diester can beemployed in admixture with minor amounts of other oils, particularlyother synthetic oils, such as a silicone polymer oil, a polyether oil, apolyglycol oil, a polyester oil, or mixtures of said oils.

Specific details for the preparation of the copper or nickel chelatechloroor methoxy-substituted 3-chloro-2- hydroxyazobenzene compoundswill be readily apparent to those skilled in the art from the followingexamples.

EXAMPLE A The 5,3'-dichloro-2-hydroxyazobenzene starting material toprepare the copper or nickel chelate thereof was prepared in a knownmanner by diazotizing meta-chloroaniline and reacting the resultingdiazotate with parachlorophenol.

EXAMPLE B The reaction product of Example A above in an amount of 467grams was reacted with 175 grams of cupric acetate monohydrate in 500milliliters of water, 1500 milliliters of dioxane and 1500 millilitersof methanol by heating the mixture with stirring on a steam plate for 3hours. The resulting reaction product was filtered, washed with dioxaneand with methanol. The copper chelate of 5,3- dich}loro-2-hydroxyazobenzene product was a rust-red powder. The yield was 84%(439.8 grams). The copper chelate had a melting point of 294-297 C. Onanalysis, the copper content was found to be 9.91% by weight.

EXAMPLE C Following the procedure for Example B above, the nickelchelate of 5,3-dichloro-2-hydroxyazobenzene was prepared from nickelousacetate tetrahydrate and the prod- A was prepared from cupric acetatemonohydrate and 5- methoxy-3-chloro-2-hydroxyazobenzene. The yield was54.4%; M.P. 252-257 C.; 8.7% copper; 8.1% nitrogen.

EXAMPLE 1 A grease was prepared by blending 1,723 parts of a waterslurry of the copper chelate of 5,3'-dichloro-2-hydroxyazobenzeneprepared in a manner similar to Example B above, 485 parts of siliconepolymer oil (Versilube F-), and heating the blend at 250 F. for 2 hourswith stirring. The slurry contained 417 parts of the chelate and 1,306par-ts of water. The resulting blended grease was milled twice in aPremier colloid mill having a rotor-stator clearance of 0.002 inch. Theresultant product was a buttery, glossy grease. Inspection tests on thisgrease are shown in the table below.

EXAMPLES 2 TO 4 INCLUSIVE Following the procedure of Example 1 above,various greases were prepared from a silicone polymer oil, VersilubeF-50, using as thickening agents various copper and nickel chelates. Thecompositions of these greases and the particular chelate thickeners areshown in the table below.

EXAMPLE 5 A synthetic ester grease was prepared by blending 460 parts ofditridecyl sebacate with 2,365 parts of a water slurry of the copperchelate of 5,3-dichloro-2-hydroxyazobene prepared in a manner similar toExample B above and the resulting blend was heated to a temperature of250 F. The slurry contained 460 parts of the chelate and 1,905 parts ofwater. When the blend had attained this temperature, heating wasdiscontinued and 7.45 parts of diphenyl-paraphenylenediamine oxidationinhibitor and 7.45 parts of Sarkosyl LC corrosion inhibitor were addedto the heated blend with mixing. The resulting heated blend was milledfor '2, passes through a Premier colloid mill having a clearance of0.002 inch. Inspection tests on the resulting grease are shown in the 40table below.

Table Example 1 Example 2 Example 3 Example 4 Example 5 Composition, wt.percent:

Versilube F50. 69.1 60.0 58.9 00.0 Formamide 1.0 Diplienylp-phenylenedi- 0.6.

amine.

Penetration, unworked Worked, strokes 105 strokes Dropping point, FDynamic H2O resist., percent loss. Water absorb, percent abs... Oilseparation, 30 hrs., 450 F., percent loss. Oil evaporation, 22 hrs., 400F., percent loss.

ASMT bomb 0x., 100 hrs., 2 0 2 (210 F.) 0. (210 F.) 1.

250 F.. p.s.i. drop. Copper Corrosion Pass (elean) StorageStability-Penetration unworked (worked): 1

Original; 285 (317) 272 (305). 1 week 21-5 (287). 1 montlL- (253) 257(283) 3 1nontl1s (257) 6 months (315)..

1 Floeeulation agent.

2 cone, worker.

*A-Copper 5,3"dichloro-2-hydroxyazobenzene. *BNiekel5,3-diehloro-Z-hydroxyazobenzene. (J-Copper5-methoxy-3-chloro-2-hydroxyazobcnzene.

net of Example A above. The chelate was obtained in 68% yield; M.P.293-296 C.

EXAMPLE D Following the procedure of Example B above, the copper chelateof 5-methoxy-3'-chloro-2-hydroxyazobcnzene 3-chloro-2-hydroxyazobenzeneare satisfactory thickening agents for silicone polymer and diester baseoils to form stable grease.

The grease composition of Example 1 was a buttery No. 3 grade greasethat exhibited a high dropping point, excellent oxidation and corrosionresistance and low oil separation and evaporation properties in thetests. The shear stability, water resistance and storage test resultswere good.

Inspection of the test results shown in the table above, show that thegrease composition of Example 2 also exhibited desirable greaseproperties.

The grease of Example 3 was a No. 2 grade grease having excellentdropping point, water resistance, oil separation and oxidation values inthe tests.

The grease composition of Example 4 exhibits good shear stability,oxidation resistance and water resistance. This grease was a No. 3gradegrease having a dropping point of 450 F.

The grease of Example 5 above was a buttery No. 2 grade grease. Thisgrease composition had a high dropping point, good oxidation resistance,water sensitivity, and shear stability as shown in the above table.

Additional experiments were conducted to evaluate other copper andnickel chelates of similarly substituted 2-hydroxyazobenzenes.

The following compounds were tested in Versilube F-SO base oil as greasethickening agents, but the results were completely unsatisfactory. Fluidand semi-fluid systems were obtained using the following chelates inVersilube F-SO base oil.

39.6% of the copper chelate of 5,4-dichloro-2-hydroxyazobenzene;

39.7% of the corresponding nickel chelate; v

39.6% of the nickel chelate of 5-methoxy-3'-chloro-2-hydroxyazobenzene;

39.5 and 39.7%, respectively of the nickel chelate of 5-chloroa2'-methoxy-2-hydroxyazobenzene.

These tests serve to demonstrate the specificity of the particularcopper S-chloro-substituted, copper S-methoxysubstituted, as well as thenickel S-chloro-substituted 3'- chloro 2 hydroxyazobenzene compounds asthickening agents in the compositions of the invention.

Obviously, many modifications and variations of the invention, ashereinbefore set forth, may be made without departing from the spiritand scope thereof and therefore, only such limitations should be imposedas are indicated in the appended claims.

We claim:

1. A lubricating grease composition comprising a synthetic base oilhaving a viscosity in the lubricating oil viscosity range containing acompound selected from the group consisting of the copper and nickelchelates of 5,3- dichloro-2-hydroxyazobenzene and the copper chelate of5-methoxy-3'-chloro-2-hydroxyazobenzene in an amount sufficient tothicken said base oil to a grease consistency.

2. A grease composition as claimed in claim 1 wherein the synthetic baseoil comprises from about to percent by weight and the metal chelatethickening agent comprises from about 15 to 45 percent by weight, basedon the weight of the composition.

3. A grease composition as claimed in claim 1 wherein the thickeningagent is the copper chelate of 5,3'-dichloro- Z-hydroxyazobenzene.

4. A grease composition as claimed in claim 1 wherein the thickeningagent is the copper chelate of S-methoxy- 3-chloro-2-hydroxyazobenzene.

5. A grease composition in accordance with claim 1 wherein thethickening agent is the nickel chelate of5,3'-dichloro-2-hydroxyazobenzene.

6. A grease composition as claimed in claim 1 wherein the synthetic baseoil is a silicone polymer oil having a viscosity in the lubricating oilviscosity range.

7. A grease composition as claimed in claim 5 wherein the siliconepolymer oil is a methylchlorophenylsilicone polymer oil having aviscosity in the range of from about to 600 seconds, Saybolt Universalat 100 F.

8. A grease composition as claimed in claim 1 wherein the syntheticlubricating oil is ditridecyl sebacate.

9. A grease composition comprising from about 59 to 69 percent by weightof a methylchlorophenylsilicone polymer oil having a viscosity in thelubricating oil viscosity range, thickened to a grease consistency withfrom 30 to 40 percent by weight of a copper chelate of 5,3-dichloro-Z-hydroxyazobenzene, and containing about 0.5 percent by weightof an amine oxidation inhibitor, and

about 0.5 percent by weight of a sarcosine corrosion inhibitor.

10. A grease composition as claimed in claim 9 wherein the amineoxidation inhibitor is diphenyl-paraphenylenediamine.

11. A grease composition as claimed in claim 9 wherein the sarcosinecorrosion inhibitor is N-cocoylsarcosine.

DANIEL E. WYMAN, Primary Examiner.

1. A LUBRICATING GREASE COMPOSITION COMPRISING A SYNTHETIC BASE OILHAVING A VISCOSITY IN THE LUBRICATING OIL VISCOSITY RANGE CONTAINING ACOMPOUND SELECTED FROM THE GROUP CONSISTING OF THE COPPER AND NICKELCHELATES OF 5,3''DICHLORO-2-HYDROXYAZOBENZENE AND THE COPPER CHELATE OF5-METHOXY-3''-CHLORO-2-HHDROXYAZOBENZENE IN AN AMOUNT SUFFICIENT TOTHICKEN SAID BASE OIL TO A GREASE CONSISTENCY.